1. Field of the Invention
The present invention relates to a communication system and method. More particularly, the present invention relates to a communication system, femto cell, and clustering and handover method of the same.
2. Description of the Related Art
Typically, a mobile communication system is composed of a plurality of macro cells each of which is managed by a macro base station (e.g., evolved Node B (eNB)). The eNB provides the communication terminals (User Equipment (UE)) with communication service. In a communication system, the UE experiences change of signal environment in a specific cell, however the macro eNB serves the UE without consideration of the UE-specific signal environment. This is likely to cause communication service quality degradation and delay.
This problem can be mitigated by installing an intermediate device, such as for example, a repeater and a remote unit, between the macro eNB and UE. The macro eNB and intermediate device are installed by the service provider and result in an increase of service cost. Furthermore, the introduction of the extra device derives interoperability issue between the macro eNB and the intermediate device.
In order to solve these problems, it is proposed to deploy femto eNB(s) within the macro cell managed by the macro eNB. The femto eNB is an indoor base station installed at an area with weak macro eNB signal or shadow such as inside of a house or a building. Typically, the femto eNB is configured to provide the communication service to the UEs that have been registered with the communication system in advance.
This means that the registered UE is capable of being served by both the macro eNB and the femto eNB. In order to accomplish this, it is necessary for the communication system to support handover between macro and femto eNBs and between femto eNBs as well as between macro eNBs. Because the registered UE is capable of being served by both the macro eNB and the femto eNB, if a communication supported handovers between femto eNBs and between macro eNBs, it can be expected to improve the communication service quality in the communication system.
However, the communication system according to the related art does not support the inter-femto eNB handover of the UE. Accordingly, when the UE enters a weak signal area of the macro eNB or a shadow area, it is necessary to perform the handover from the femto eNB to the macro eNB and then the handover from the macro eNB to another femto eNB. This causes the degradation of seamless connectivity of the communication service to the UE.
There is therefore a need of a method for securing robust communication service connectivity of a UE in a communication system.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention.